Emergency shelter in the form of a tent or the like



l Unlted States Patent 1 1 3,547,136

[72) Inventors Hans Prinz (56] References Cited m We R h R d If UNITEDSTATES PATENTS "3" i 315,679 4/l885 Upton H 174/2 g f 'xf Upper3,058,480 10/1962 Blanchard 2 135/1 3,139,948 7/1964 Rordcn i. l82/46X 13 3,390,491 7/1968 Hayden e161. 52/2 [22] ed 1,553,087 9/1925 Lehmann174/2 [45] Patented Dec. 15,1970 ENTS (73] Assignee Dehn 8: Siiehne,FOREIGN PAT Nurnberg, Germany 683,630 3/1930 France l74/2 [32% Priorityug. 12,1967, Feb. 7, 1968 Primary Emminer pemr M- Caun (33 At: R b tH.Jb 311 N05. 1,557,383 and 1,632,485

[54] SHELTER IN THE FORM OFATENT ABSTRACT: A tent, or a shelter similarto a tent, where i 60 Fi means are provided to protect the occupant, oroccupants, a r mg against lightning bolts, which tent is in the form ofaFaraday [52] [1.8. CI 135/1 cage and the components constituting thecage are conduc- [51] lnt.l A45flll/00; tively connected to ground, oradapted to be connected to E04b0l/347 ground, and which generallycomprises a metal frame and a [50) Field of Search 135/1; 52/2; coverthat is preferably conductive for electricity and a metallic base orfloor.

PATENTEUDEBISISTU 3,547,135

sum 1 or 4 Inventors.- HA/V firm/z, JMA/M/AS' PATENTEU DEC! 5 I970 SHEETQ UF 4 Inventors.-

EMERGENCY SHELTER IN THE FORM OF A TENT OR THE LIKE BACKGROUND OF THEINVENTION The present invention relates to tents or tent like emergencyshelters. More in particular, this invention concerns a tent or tentlike emergency shelter (for convenience only the expression tent will beused hereinafter), with means of protection against lightening strokesfor the people using the tent. For reduction of the step voltagegradient (the potential difference over the length of an average humanstep), it has already been proposed, to make the base of the shelterentirely or partly out of an electrically conductive material. However,with this preventive measure no adequate protection is given the peoplewhich are in the shelter, as it lacks protection against a lighteningstrike directly in the tent.

SUMMARY OF THE INVENTION It is therefore an object of the presentinvention to provide by simple means, a tent that protects the peoplewho are inside not only against the effect of a direct lighteningstroke, but also reliably prevents the pickup of a dangerousstep-voltage gradient. The protective devices against lightening shouldnot however result in a substantial increase in the production cost, notcause any marked complications while setting up or dismantling the tent,as well as not be too unwieldy or heavy.

Therefore in accordance with the invention, the tent is formed likeFaraday's cage (an electrostatic screen) and the cagelike portions arein a conductive connection with or are connectable with the earth. Thiscontact requirement can be accomplished by means of extending the tentpoles or frame to the ground, and/or a metallic grounding plate or alsowith metal litz wire and the like, so that the passage of the lighteningbolt to ground at a definite point is insured.

The Faraday's cage can be formed in a simple manner by the tent frame.for example suitable metal parts or tubes and/or by the covering fabric.For this the combination of a tent frame with an electrically conductivetent cover has been found to be especially satisfactory. To this end itis proposed for an especially preferred embodiment of the invention,that a safety tent forming the Faraday cage is located inside the frameand disposed at a distance therefrom, which is electri cally connectedin at least one place with the frame. Several advantages are thusobtained. The frame, which may also be in the form of a cage, servesalone as the conductor of the lightening bolt, which accordingly is notled over the tent cover. The safety tent completely shields the userelectrically and has the same electrical potential at all points. Thusthe user in the interior can not receive a dangerous step voltage nor beendangered by contact with the tent cover.

The tent, according to the invention can be built to shelter one or morepersons. For this production in the form of a semisphere or theso-called igloo is recommended as electrically especially favorable, butthe invention is not limited thereto. A tent of low structural heightlike the aforementioned igloo form, has the advantage that with it thedanger of a lightening bolt as well as the danger of being crushed orturned over by a storm is diminished.

The invention can be utilized to advantage not only for camping tentsbut also for other purposes. Such simple and easily assembled tents oremergency shelters can serve above all as protection against weather andlightening for those working or active in the open. as railroadpersonnel, telephone or electrical linemen, lumberjacks, farmers,fishermen, hunters, the military, border guards, mountain rangers, andso on.

A one man tent made according to the invention weighs only a fewkilograms and is storable in a handy carrying case, so that it can bereadily carried by one person over long distances. Thus lighteningprotected emergency shelters, or so-called bivouac shelters can also beproduced for hikers or mountain climbers caught in stormy weather. It isevident that emergency shelters of this type must not necessarily beadapted to be dismantled, as they may also be provided with a unitaryframe to be set up in situ.

Further advantages and details of the invention will become apparent byreference to the embodiments illustrated in the accompanying drawings inwhich:

FIG. I is a perspective view of a first embodiment of a one man tent inaccordance with the invention;

FIG. 2 shows a second embodiment of the invention with the tent coveromitted also in perspective;

FIG. 3 shows schematically and also in perspective a third embodiment ofthe invention;

FIG. 4 shows schematically a plan view of a tent cor responding to theembodiment in accordance with FIG. 3, but with the upper tent and frameparts omitted;

FIG. 5 shows in a perspective view ofa portion ofa camping house tentwith a suspended tent unit, and

FIG. 6 shows in a schematic plan view of FIG. 5 with the tent roof andother details not of interest omitted.

The frame Ia comprising assemblable metal tubes (see FIG. 2) for examplesteel or aluminum tubes, is provided with a lightening rod 2 suitably onits highest point, and in use rests upon the ground with its groundstruts. Fundamentally other means for establishing a connection betweenthe frame or tent and the ground would also be possible.

In this embodiment the frame Ia has the task of intercepting andconducting directly striking bolts of lightening and conducts theircurrent immediately to ground so that the tent will not be touchedthereby. Moreover, the frame la can also take on the function of aFaraday cage for lightening bolts striking in the proximity.

In the frame 1 as illustrated in FIG. 1, the tent 3 is so arranged,preferably hung in, that it is spaced a distance a therefrom tosafeguard against jumping of a lightening bolt. Taking intoconsideration the strength of the usual lightening bolt, it willgenerally be sufficient, if this distance is a few cen timeters. It ishowever to be understood that the invention is not limited thereto asevidenced by the other embodiments illustrated.

The frame is suitably made of metal tubes or rods that are connectedtogether by sockets or sleeves 24 as illustrated in FIG. 2 at la.

The transverse struts I" of the frame are hingedly connected at 25 tothe ground plate 17' as seen in FIGS. 3 and 4.

As seen in FIG. 2 the tent cover 3 is below the frame In, although itcan also rest on the frame.

The safety tent in the form ofa Faraday cage comprises, for example, amctallized fabric, for which a cloth can be utilized, that has metalthread 21, 22 woven into the weft and also into the warp as in FIG. 1.Metal litz wires 19 sewn on may also be as shown in FIG. 3.

The tent covering fabric can also be formed to be entirely electricallyconductive by other means, for example, by production from a materialwhich is conductive per se, applied with a brush, spraying on a metalcoating, or covering with a layer of metal 20 as indicated in FIG. 2.

According to the embodiment of FIG. I, the tent 3 is fastened to frame Iby releasable loops 5, which consist of an insulating material likerubber or plastic. The material of this suspending means can be rigid orelastic. On or in floor 3' of the safety tent a conductive floorcovering such as, one provided with litz wire can be disposed.Especially appropriate is the use of a mctallized rubber mat I]. Bythese means, the relatively delicate tent cloth is protected thereagainst stepping through or other mechanical damage. Simultaneously thepenetration into the interior of the tent of moisture and rainwatercollected on the ground is prevented. In order to give the tent 3 adefinite electrical potential, it is connected with the frame at anyplace. As FIG. 1 illustrates, this connection 6 can consist of metallitz 7 sewn on the tent and fastened of the frame 1 near the ground. Themctallized tent cover, which is conductively connected to the frame Iand surrounds the occupants, prevents that any displacement currents dueto the increase in potential of the frame 1 with respect to theenvironment can flow over the occupants, especially through any contactpoints between the occupants and the tent frame, and can seriouslyendanger the people. Additionally it should be pointed out that theconductive tent cover protects the occupants also against Vagabondcurrents which possibly occur if the tent is set up under trees havingbranches hanging down or in bushes.

The embodiments of FIGS. I and 2 each show a tent for accommodating oneperson. This tent is suitably in the approximate shaped of a semisphereor an igloo where the seating cushion 9 for the occupant can be in onecorner and the windows 4 to the left and the right of the oppositecorner. The seat 9 is suitably made of an insulating material, forexample, a cushion of rubber or plastic that can be blown up. On a sidewall the entrance flap I6 is provided with a zipper 8 which can beclosed from the inside as well as from the outside. It is, of course,also possible to make larger tent units in this manner. Furthermore, theinvention is not limited to the illustrated form and configuration ofthe frame.

Moreover, as shown in FIG. 2 a ground plate l7 can be provided which islocated in the interior of the tent and there constitutes a standing orlocating surface for the feet of the tent occupant or occupants. Sizeand arrangement of the tent, as well as of the chosen plate 17 and ofthe seat 9 may be chosen in such a manner in relation to the tentinterior, that the occupant or occupants can assume a definite positionin the tent and place the feet upon the ground plate (see FIG. 2 and theschematic drawing of FIG. 4). Thus the user is prevented from picking upa step voltage, while the Faraday cage affords a safeguard againstdirect lightening strokes. It is advisable not to make the ground platetoo large, so that there is only room for the feet of the person orpersons that can be accommodated in the interior of the tent.

The electrical connection of the ground plate with the earth can beoptional, for example, by way of the base or ground struts l of theframe Ia, which may simultaneously serve for grounding the frame or theFaraday cage. The ground plate 17 can be releasably connected with thestruts I. For this purpose the plate 17 may be arcuated as indicated inFIG. 2 at 18 and resilient.

In the possibilities of embodiments for multiple occupancy tentsillustrated in FIGS. 3 and 4, on the other hand, the differently shapedtransverse struts I" of the frame lb are linked to the plates 17' andcan be turned over downwardly or upwardly into a position perpendicularto the plate for transportation purposes.

In the embodiment in accordance with FIG. 2 the tent cover 3 is directlybelow the frame Ia and may be a Faraday cage. If the frame, as well asalso the tent cover are designed as a Faraday cage, it is advisable toconnect them conductively at several places. It would also be possibleto provide the tent cover on the outside of the frame lb as indicated at3" in FIG. 3. In that event the cover must have the properties of aFaraday cage.

Fundamentally the mesh width of the Faraday cage should be so narrowthat no dangerous potential difference can arise between the person andthe cage. Since the tent has merely a contact ground, it is under someconditions raised to several million volts when a lightening boltstrikes. A suitably narrow meshed cage safeguards against the personbeing "taken along" to this voltage, i.e., a sufficient coupling isprovided between person and tent. In that event (see also the embodimentof FIG. I) there is no necessity for electrical reasons to provide aground plate or the like in the tent that is conductively connected toground so that the tent can also be closed entirely at the bottom andthus be satisfactorily sealed against the penetration of wind anddampness.

It is furthermore accomplished with a strut arrangement in accordancewith FIGS. 1-4 that the tent is safely held on the ground by the weightof the occupant or occupants seated therein, i.e., it need not beseparately anchored. This is essential because in the event of asuddenly arising storm the time is the frame, possibl the ground plateand the cover can be readily accommo ated and taken along in a portablecon tainer such as a knapsack, a bag or the like.

The embodiment in accordance with FIGS. 5 and 6 illus trates theapplication of the invention, to a tent generally referred to as a housetent for camping purposes. In the outer camping tent 12 the supportingframe I3 is indicated in interrupted lines. Onto this frame a living orsleeping unit 15 is tied by means of loops 14 which are onlyschematically illustrated (dash and dot lines), which unit is in thesense of the above explanations in the form of a Faraday cage made, forexample, out of metallized fabric. The inner tent part 15 may be madeeither as a separate living or sleeping unit and hung into camping tentsthat are already in existence. However, it is also possible to providesuch a camping tent from the beginning with a tent portion in the formof a Faraday cage hung into its frame. Particularly in the tentembodiments described above, it is advantageous to place a mesh screen23 below the rubber bottom of the tent. In general, the featuresdescribed in connection with the embodiments of FIGS. 1-4 may be appliedin the same sense also to the embodiments of FIGS. 5 and 6 and viceversa.

The dimensional proportions of the mesh screen should be such that itcan conduct the lightening current which flows over the frame intoground. Only by way of example a mesh screen is mentioned made of copperlitzen that is 5mm in cross section and ofa mesh width of 3050cm.', theinvention is not limited thereto. By means of the mesh screen dangerousstep potentials are simultaneously avoided.

Having now described our invention with reference to the embodimentsillustrated in the drawings, what we desire to protect by letters patentof the United States is set forth in the appended claims.

We claim:

1. Shelter in the form of a tent providing protection for the occupantor occupants against lightning strokes, said shelter comprising asupporting frame, a conductive floor including metal capable ofconducting lightning currents conductively connected to said frame, ashelter cover, insulating members such as loops of rubber or plasticmaterial supporting said shelter cover on said frame at a distance tosafeguard against jumping of lightning bolts, said frame and said floorforming a Faraday cage adapted to be conductively connected to ground.

2. Shelter in accordance with claim I. where said shelter cover is madeof an electrically conductive material.

3. Shelter in accordance with claim 1, where the distance between saidshelter cover and said frame is a few centimeters.

4. Shelter in accordance with claim 1 wherein said metal in saidconductive floor is in the form of a ground plate or the like in theinterior of said shelter which serves as a supporting surface for thefeet of the occupant or occupants of said shelter.

5. Shelter in accordance with claim 4 comprising conductor means such asmetallic struts conductively connecting said ground plate to said frame.

6. Shelter in accordance with claim 4 including an inflatable seat foreach occupant arranged proximate said ground plate in a mannerpermitting the occupant of each seat to place his feet on said groundplate.

7. Shelter in accordance with claim 1, where said safety shelter isincorporated in a camping tent unit to form a room and includes meansfor supporting said shelter on said frame.

8. Shelter in accordance with claim 1 wherein said conductive floor isin the form of a mesh screen connected with said frame.

